The last few years have witnessed an enormous interest in application of GIS in hydrology and water resources. This is partly evidenced by organization of sev eral national and international symposia or conferences under the sponsorship of various professional organizations. This increased interest is, in a large measure, in response to growing public sensitivity to environmental quality and management. The GIS technology has the ability to capture, store, manipulate, analyze, and visualize the diverse sets of geo-referenced data. On the other hand, hydrology is inherently spatial and distributed hydrologic models have large data requirements. The integration of hydrology and GIS is therefore quite natural. The integration involves three major components: (1) spatial data construction, (2) integration of spatial model layers, and (3) GIS and model interface. GIS can assist in design, calibration, modification and comparison of models. This integration is spreading worldwide and is expected to accelerate in the foreseeable future. Substantial op portunities exist in integration of GIS and hydrology. We believe there are enough challenges in use of GIS for conceptualizing and modeling complex hydrologic processes and for globalization of hydrology. The motivation for this book grew out of the desire to provide under one cover a range of applications of GIS tech nology in hydrology. It is hoped that the book will stimulate others to write more comprehensive texts on this subject of growing importance.

The assessment of the ecological integrity of running waters is a prerequisite to an understanding of the effects of human alterations. The evaluation of degradation processes provides key information on how to avoid further negative impacts. The success of future conservation, mitigation and restoration activities will rely on sound assessment methodologies and their ecological relevance and applicability. Assessment methodologies are therefore an integral part of sustainable river management. This book synthesizes and discusses state-of-the-art experiences in assessment methodologies. Including the latest knowledge on structures, processes and functions of running waters as a fundamental basis for developing adequate assessment methods, the book focuses on method development, application, and in particular on integrated assessment methods. This book is directed at scientists and managers with the aim of more effective preservation, restoration and maintenance of the ecological integrity of running water ecosystems.